Low power computer with main and auxiliary processors

ABSTRACT

A processing device comprises a processor, low power nonvolatile memory that communicates with the processor, high power nonvolatile memory that communicates with the processor. The processing device manages data using a cache hierarchy comprising a high power (HP) nonvolatile memory level for data in the high power nonvolatile memory and a low power (LP) nonvolatile memory level for data in the low power nonvolatile memory. The LP nonvolatile memory level has a higher level in the cache hierarchy than the HP nonvolatile memory level.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.10/865,732, filed Jun. 10, 2004. This application is related to U.S.patent application Ser. No. 10/779,544, filed Feb. 13, 2004 and U.S.patent application Ser. No. 10/865,368, filed Jun. 10, 2004. Thedisclosures of the above application are incorporated herein byreference in their entirety.

FIELD OF THE INVENTION

The present invention relates to computer architectures, and moreparticularly to dual power mode computer architectures.

BACKGROUND OF THE INVENTION

Laptop computers are powered using both line power and battery power.The processor, graphics processor, memory and display of the laptopcomputer consume a significant amount of power during operation. Onesignificant limitation of laptop computers relates to the amount of timethat the laptop can be operated using batteries without recharging. Therelatively high power dissipation of the laptop computer usuallycorresponds to a relatively short battery life.

Referring now to FIG. 1A, an exemplary computer architecture 4 is shownto include a processor 6 with memory 7 such as cache. The processor 6communicates with an input/output (I/O) interface 8. Volatile memory 9such as random access memory (RAM) 10 and/or other suitable electronicdata storage also communicates with the interface 8. A graphicsprocessor 11 and memory 12 such as cache increase the speed of graphicsprocessing and performance.

One or more I/O devices such as a keyboard 13 and a pointing device 14(such as a mouse and/or other suitable device) communicate with theinterface 8. A high power disk drive (HPDD) 15 such as a hard disk drivehaving one or more platters with a diameter greater than 1.8″ providesnonvolatile memory, stores data and communicates with the interface 8.The HPDD 15 typically consumes a relatively high amount of power duringoperation. When operating on batteries, frequent use of the HPDD 15 willsignificantly decrease battery life. The computer architecture 4 alsoincludes a display 16, an audio output device 17 such as audio speakersand/or other input/output devices that are generally identified at 18.

Referring now to FIG. 1B, an exemplary computer architecture 20 includesa processing chipset 22 and an I/O chipset 24. For example, the computerarchitecture may be a Northbridge/Southbridge architecture (with theprocessing chipset corresponding to the Northbridge chipset and the I/Ochipset corresponding to the Southbridge chipset) or other similararchitecture. The processing chipset 22 communicates with a processor 25and a graphics processor 26 via a system bus 27. The processing chipset22 controls interaction with volatile memory 28 (such as external DRAMor other memory), a Peripheral Component Interconnect (PCI) bus 30,and/or Level 2 cache 32. Level 1 cache 33 and 34 may be associated withthe processor 25 and/or the graphics processor 26, respectively. In analternate embodiment, an Accelerated Graphics Port (AGP) (not shown)communicates with the processing chipset 22 instead of and/or inaddition to the graphics processor 26. The processing chipset 22 istypically but not necessarily implemented using multiple chips. PCIslots 36 interface with the PCI bus 30.

The I/O chipset 24 manages the basic forms of input/output (I/O). TheI/O chipset 24 communicates with an Universal Serial Bus (USB) 40, anaudio device 41, a keyboard (KBD) and/or pointing device 42, and a BasicInput/Output System (BIOS) 43 via an Industry Standard Architecture(ISA) bus 44. Unlike the processing chipset 22, the I/O chipset 24 istypically (but not necessarily) implemented using a single chip, whichis connected to the PCI bus 30. A HPDD 50 such as a hard disk drive alsocommunicates with the I/O chipset 24. The HPDD 50 stores a full-featuredoperating system (OS) such as Windows XP® Windows 2000®, Linux andMAC®-based OS that is executed by the processor 25.

SUMMARY OF THE INVENTION

A processing device comprises a primary processor that consumes power ata first rate and that is operated when the computer is in an high powermode. The processing device includes a secondary processor that consumespower at a second rate that is less than the first rate and that isoperated when the computer is in the low power mode.

In other features, the primary processor is fabricated using a firstprocess and the secondary processor is fabricated using a secondprocess. The first process has smaller feature sizes than the secondprocess. A primary graphics processor communicates with the primaryprocessor and is operated when the computer is in the high power mode.The primary processor and the primary graphics processor are notoperated when the computer is in the low power mode. A secondarygraphics processor communicates with the secondary processor and isoperated during the low power mode.

In other features, primary volatile memory communicates with the primaryprocessor during the high power mode and with the secondary processorduring the low power mode. Primary volatile memory communicates with theprimary processor during the high power mode and secondary volatilememory communicates with the secondary processor during the low powermode.

In yet other features, primary volatile memory communicates with theprimary processor during the high power mode. Secondary volatile memoryis embedded in the secondary processor. A processing chipsetcommunicates with the primary processor and the primary graphicsprocessor during the high power mode and with the secondary processorand the secondary graphics processor during the low power mode. An I/Ochipset communicates with the secondary processor and the secondarygraphics processor during the low power mode.

In still other features, transistors of the primary processor areoperated at less than approximately 20% duty cycle and transistors ofthe secondary processor are operated at greater than approximately 80%duty cycle. Transistors of the primary processor are operated at lessthan approximately 10% duty cycle and transistors of the secondaryprocessor are operated at greater than approximately 90% duty cycle.

In yet other features, the primary processor executes a full-featuredoperating system during the high power mode and the secondary processorexecutes a restricted-feature operating system during the low powermode.

In other features, at least one of a low power disk drive and/or flashmemory communicates with the secondary processor and stores arestricted-feature operating system that is executed by the secondaryprocessor during the low power mode. A high power disk drivecommunicates with the primary processor and stores a full-featuredoperating system that is executed by the primary processor during thehigh power mode. Level one cache is associated with the primaryprocessor. Level two cache communicates with the primary processor.

In other features, the processing device employs a cache hierarchycomprising a high power (HP) nonvolatile memory level for data in the HPnonvolatile memory, a low power (LP) nonvolatile memory level for datain the LP nonvolatile memory, a volatile memory level, a second levelfor data in the level two cache, a first level for data in the level onecache, and a CPU level for data in at least one of the primary processorand/or the secondary processor.

In still other features, primary volatile memory communicates with theprimary processor. The volatile memory level corresponds to data in theprimary volatile memory during the high power mode. Secondary volatilememory communicates with the secondary processor. The volatile memorylevel corresponds to data in the secondary volatile memory during thelow power mode. Secondary volatile memory is embedded in the secondaryprocessor. The volatile memory level corresponds to data in the embeddedsecondary volatile memory during the low power mode.

In other features, the full-featured operating system and therestricted-feature operating system share a common data format.

In other features, the HP nonvolatile memory includes a high power diskdrive with a platter having a diameter greater than 1.8″ and the LPnonvolatile memory includes at least one of flash memory and/or a lowpower disk drive having a platter with a diameter less than or equal to1.8″.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIGS. 1A and 1B illustrate exemplary computer architectures according tothe prior art;

FIG. 2A illustrates a first exemplary computer architecture according tothe present invention with a primary processor, a primary graphicsprocessor, and primary volatile memory that operate during an high powermode and a secondary processor and a secondary graphics processor thatcommunicate with the primary processor, that operate during a low powermode and that employ the primary volatile memory during the low powermode;

FIG. 2B illustrates a second exemplary computer architecture accordingto the present invention that is similar to FIG. 2A and that includessecondary volatile memory that is connected to the secondary processorand/or the secondary graphics processor;

FIG. 2C illustrates a third exemplary computer architecture according tothe present invention that is similar to FIG. 2A and that includesembedded volatile memory that is associated with the secondary processorand/or the secondary graphics processor;

FIG. 3A illustrates a fourth exemplary architecture according to thepresent invention for a computer with a primary processor, a primarygraphics processor, and primary volatile memory that operate during anhigh power mode and a secondary processor and a secondary graphicsprocessor that communicate with a processing chipset, that operateduring the low power mode and that employ the primary volatile memoryduring the low power mode;

FIG. 3B illustrates a fifth exemplary computer architecture according tothe present invention that is similar to FIG. 3A and that includessecondary volatile memory connected to the secondary processor and/orthe secondary graphics processor;

FIG. 3C illustrates a sixth exemplary computer architecture according tothe present invention that is similar to FIG. 3A and that includesembedded volatile memory that is associated with the secondary processorand/or the secondary graphics processor;

FIG. 4A illustrates a seventh exemplary architecture according to thepresent invention for a computer with a secondary processor and asecondary graphics processor that communicate with an I/O chipset, thatoperate during the low power mode and that employ the primary volatilememory during the low power mode;

FIG. 4B illustrates an eighth exemplary computer architecture accordingto the present invention that is similar to FIG. 4A and that includessecondary volatile memory connected to the secondary processor and/orthe secondary graphics processor;

FIG. 4C illustrates a ninth exemplary computer architecture according tothe present invention that is similar to FIG. 4A and that includesembedded volatile memory that is associated with the secondary processorand/or the secondary graphics processor; and

FIG. 5 illustrates a caching hierarchy according to the presentinvention for the computer architectures of FIGS. 2A-4C;

FIG. 6 is a functional block diagram of a drive control module thatincludes a least used block (LUB) module and that manages storage andtransfer of data between the low-power disk drive (LPDD) and thehigh-power disk drive (HPDD);

FIG. 7A is a flowchart illustrating steps that are performed by thedrive control module of FIG. 6;

FIG. 7B is a flowchart illustrating alternative steps that are performedby the drive control module of FIG. 6;

FIGS. 7C and 7D are flowcharts illustrating alternative steps that areperformed by the drive control module of FIG. 6;

FIG. 8A illustrates a cache control module that includes an adaptivestorage control module and that controls storage and transfer of databetween the LPDD and HPDD;

FIG. 8B illustrates an operating system that includes an adaptivestorage control module and that controls storage and transfer of databetween the LPDD and the HPDD;

FIG. 8C illustrates a host control module that includes an adaptivestorage control module and that controls storage and transfer of databetween the LPDD and HPDD;

FIG. 9 illustrates steps performed by the adaptive storage controlmodules of FIGS. 8A-8C;

FIG. 10 is an exemplary table illustrating one method for determiningthe likelihood that a program or file will be used during the low powermode;

FIG. 11A illustrates a cache control module that includes a disk drivepower reduction module;

FIG. 11B illustrates an operating system that includes a disk drivepower reduction module;

FIG. 11C illustrates a host control module that includes a disk drivepower reduction module;

FIG. 12 illustrates steps performed by the disk drive power reductionmodules of FIGS. 11A-11C;

FIG. 13 illustrates a multi-disk drive system including a high-powerdisk drive (HPDD) and a lower power disk drive (LPDD);

FIGS. 14-17 illustrate other exemplary implementations of the multi-diskdrive system of FIG. 13;

FIG. 18 illustrates the use of low power nonvolatile memory such asFlash memory or a low power disk drive (LPDD) for increasing virtualmemory of a computer;

FIGS. 19 and 20 illustrates steps performed by the operating system toallocate and use the virtual memory of FIG. 18;

FIG. 21 is a functional block diagram of a Redundant Array ofIndependent Disks (RAID) system according to the prior art;

FIG. 22A is a functional block diagram of an exemplary RAID systemaccording to the present invention with a disk array including X HPDDand a disk array including Y LPDD;

FIG. 22B is a functional block diagram of the RAID system of FIG. 22Awhere X and Y are equal to Z;

FIG. 23A is a functional block diagram of another exemplary RAID systemaccording to the present invention with a disk array including Y LPDDthat communicates with a disk array including X HPDD;

FIG. 23B is a functional block diagram of the RAID system of FIG. 23Awhere X and Y are equal to Z;

FIG. 24A is a functional block diagram of still another exemplary RAIDsystem according to the present invention with a disk array including XHPDD that communicate with a disk array including Y LPDD;

FIG. 24B is a functional block diagram of the RAID system of FIG. 24Awhere X and Y are equal to Z;

FIG. 25 is a functional block diagram of a network attachable storage(NAS) system according to the prior art; and

FIG. 26 is a functional block diagram of a network attachable storage(NAS) system according to the present invention that includes the RAIDsystem of FIGS. 22A, 22B, 23A, 23B, 24A, and/or 24B and/or a multi-drivesystem according to FIGS. 6-17.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiment(s) is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses. For purposes of clarity, the same referencenumbers will be used in the drawings to identify similar elements. Asused herein, the term module refers to an application specificintegrated circuit (ASIC), an electronic circuit, a processor (shared,dedicated, or group) and memory that execute one or more software orfirmware programs, a combinational logic circuit, and/or other suitablecomponents that provide the described functionality.

As used herein, data processing device refers to any system thatincludes a processor, memory and an input/output interface. Exemplaryprocessing devices include but are not limited to desktop computers,laptops, personal media players, personal digital assistants, andnotebooks, although still other types of processing devices arecontemplated. As used herein, the term “high power mode” refers toactive operation of the primary processor and/or the primary graphicsprocessor of the processing device. The term “low power mode” refers tolow-power hibernating modes, off modes, and/or non-responsive modes ofthe primary processor and/or primary graphics processor when a secondaryprocessor and a secondary graphics processor are operable. An “off mode”refers to situations when both the primary and secondary processors areoff.

The term “low power disk drive” or LPDD refers to disk drives and/ormicrodrives having one or more platters that have a diameter that isless than or equal to 1.8″. The term “high power disk drive” or HPDDrefers to hard disk drives having one or more platters that have adiameter that is greater than 1.8″. LPDDs typically have lower storagecapacities and dissipate less power than the HPDDs. The LPDDs are alsorotated at a higher speed than the HPDDs. For example, rotational speedsof 10,000-20,000 RPM or greater can be achieved with LPDDs.

The computer architecture according to the present invention includesthe primary processor, the primary graphics processor, and the primarymemory (as described in conjunction with FIGS. 1A and 1B), which operateduring the high power mode. A secondary processor and a secondarygraphics processor are operated during the low power mode. The secondaryprocessor and the secondary graphics processor may be connected tovarious components of the computer, as will be described below. Primaryvolatile memory may be used by the secondary processor and the secondarygraphics processor during the low power mode. Alternatively, secondaryvolatile memory, such as DRAM and/or embedded secondary volatile memorysuch as embedded DRAM can be used, as will be described below.

The primary processor and the primary graphics processor dissipaterelatively high power when operating in the high power mode. The primaryprocessor and the primary graphics processor execute a full-featuredoperating system (OS) that requires a relatively large amount ofexternal memory. The primary processor and the primary graphicsprocessor support high performance operation including complexcomputations and advanced graphics. The full-featured OS can be aWindows®-based OS such as Windows XP®, a Linux-based OS, a MAC®-based OSand the like. The full-featured OS is stored in the HPDD 15 and/or 50.

The secondary processor and the secondary graphics processor dissipateless power (than the primary processor and primary graphics processor)during the low power mode. The secondary processor and the secondarygraphics processor operate a restricted-feature operating system (OS)that requires a relatively small amount of external volatile memory. Thesecondary processor and secondary graphics processor may also use thesame OS as the primary processor. For example, a pared-down version ofthe full-featured OS may be used. The secondary processor and thesecondary graphics processor support lower performance operation, alower computation rate and less advanced graphics. For example, therestricted-feature OS can be Windows CE® or any other suitablerestricted-feature OS. The restricted-feature OS is preferably stored innonvolatile memory such as Flash memory and/or a LPDD. In a preferredembodiment, the full-featured and restricted-feature OS share a commondata format to reduce complexity.

The primary processor and/or the primary graphics processor preferablyinclude transistors that are implemented using a fabrication processwith a relatively small feature size. In one implementation, thesetransistors are implemented using an advanced CMOS fabrication process.Transistors implemented in the primary processor and/or primary graphicsprocessor have relatively high standby leakage, relatively shortchannels and are sized for high speed. The primary processor and theprimary graphics processor preferably employ predominantly dynamiclogic. In other words, they cannot be shut down. The transistors areswitched at a duty cycle that is less than approximately 20% andpreferably less than approximately 10%, although other duty cycles maybe used.

In contrast, the secondary processor and/or the secondary graphicsprocessor preferably include transistors that are implemented with afabrication process having larger feature sizes than the process usedfor the primary processor and/or primary graphics processor. In oneimplementation, these transistors are implemented using a regular CMOSfabrication process. The transistors implemented in the secondaryprocessor and/or the secondary graphics processor have relatively lowstandby leakage, relatively long channels and are sized for low powerdissipation. The secondary processor and the secondary graphicsprocessor preferably employ predominantly static logic rather thandynamic logic. The transistors are switched at a duty cycle that isgreater than 80% and preferably greater than 90%, although other dutycycles may be used.

The primary processor and the primary graphics processor dissipaterelatively high power when operated in the high power mode. Thesecondary processor and the secondary graphics processor dissipate lesspower when operating in the low power mode. In the low power mode,however, the computer architecture is capable of supporting fewerfeatures and computations and less complex graphics than when operatingin the high power mode. As can be appreciated by skilled artisans, thereare many ways of implementing the computer architecture according to thepresent invention. Therefore, skilled artisans will appreciate that thearchitectures that are described below in conjunction with FIGS. 2A-4Care merely exemplary in nature and are not limiting.

Referring now to FIG. 2A, a first exemplary computer architecture 60 isshown. The primary processor 6, the volatile memory 9 and the primarygraphics processor 11 communicate with the interface 8 and supportcomplex data and graphics processing during the high power mode. Asecondary processor 62 and a secondary graphics processor 64 communicatewith the interface 8 and support less complex data and graphicsprocessing during the low power mode. Optional nonvolatile memory 65such as a LPDD 66 and/or Flash memory 68 communicates with the interface8 and provides low power nonvolatile storage of data during the lowpower and/or high power modes. The HPDD 15 provides high power/capacitynonvolatile memory. The nonvolatile memory 65 and/or the HPDD 15 areused to store the restricted feature OS and/or other data and filesduring the low power mode.

In this embodiment, the secondary processor 62 and the secondarygraphics processor 64 employ the volatile memory 9 (or primary memory)while operating in the low-power mode. To that end, at least part of theinterface 8 is powered during the low power mode to supportcommunications with the primary memory and/or communications betweencomponents that are powered during the low power mode. For example, thekeyboard 13, the pointing device 14 and the primary display 16 may bepowered and used during the low power mode. In all of the embodimentsdescribed in conjunction with FIGS. 2A-4C, a secondary display withreduced capabilities (such as a monochrome display) and/or a secondaryinput/output device can also be provided and used during the low powermode.

Referring now to FIG. 2B, a second exemplary computer architecture 70that is similar to the architecture in FIG. 2A is shown. In thisembodiment, the secondary processor 62 and the secondary graphicsprocessor 64 communicate with secondary volatile memory 74 and/or 76.The secondary volatile memory 74 and 76 can be DRAM or other suitablememory. During the low power mode, the secondary processor 62 and thesecondary graphics processor 64 utilize the secondary volatile memory 74and/or 76, respectively, in addition to and/or instead of the primaryvolatile memory 9 shown and described in FIG. 2A.

Referring now to FIG. 2C, a third exemplary computer architecture 80that is similar to FIG. 2A is shown. The secondary processor 62 and/orsecondary graphics processor 64 include embedded volatile memory 84 and86, respectively. During the low power mode, the secondary processor 62and the secondary graphics processor 64 utilize the embedded volatilememory 84 and/or 86, respectively, in addition to and/or instead of theprimary volatile memory. In one embodiment, the embedded volatile memory84 and 86 is embedded DRAM (eDRAM), although other types of embeddedvolatile memory can be used.

Referring now to FIG. 3A, a fourth exemplary computer architecture 100according to the present invention is shown. The primary processor 25,the primary graphics processor 26, and the primary volatile memory 28communicate with the processing chipset 22 and support complex data andgraphics processing during the high power mode. A secondary processor104 and a secondary graphics processor 108 support less complex data andgraphics processing when the computer is in the low power mode. In thisembodiment, the secondary processor 104 and the secondary graphicsprocessor 108 employ the primary volatile memory 28 while operating inthe low power mode. To that end, the processing chipset 22 may be fullyand/or partially powered during the low power mode to facilitatecommunications therebetween. The HPDD 50 may be powered during the lowpower mode to provide high power volatile memory. Low power nonvolatilememory 109 (LPDD 110 and/or Flash memory 112) is connected to theprocessing chipset 22, the I/O chipset 24 or in another location andstores the restricted-feature operating system for the low power mode.

The processing chipset 22 may be fully and/or partially powered tosupport operation of the HPDD 50, the LPDD 110, and/or other componentsthat will be used during the low power mode. For example, the keyboardand/or pointing device 42 and the primary display may be used during thelow power mode.

Referring now to FIG. 3B, a fifth exemplary computer architecture 150that is similar to FIG. 3A is shown. Secondary volatile memory 154 and158 is connected to the secondary processor 104 and/or secondarygraphics processor 108, respectively. During the low power mode, thesecondary processor 104 and the secondary graphics processor 108 utilizethe secondary volatile memory 154 and 158, respectively, instead ofand/or in addition to the primary volatile memory 28. The processingchipset 22 and the primary volatile memory 28 can be shut down duringthe low power mode if desired. The secondary volatile memory 154 and 158can be DRAM or other suitable memory.

Referring now to FIG. 3C, a sixth exemplary computer architecture 170that is similar to FIG. 3A is shown. The secondary processor 104 and/orsecondary graphics processor 108 include embedded memory 174 and 176,respectively. During the low power mode, the secondary processor 104 andthe secondary graphics processor 108 utilize the embedded memory 174 and176, respectively, instead of and/or in addition to the primary volatilememory 28. In one embodiment, the embedded volatile memory 174 and 176is embedded DRAM (eDRAM), although other types of embedded memory can beused.

Referring now to FIG. 4A, a seventh exemplary computer architecture 190according to the present invention is shown. The secondary processor 104and the secondary graphics processor 108 communicate with the I/Ochipset 24 and employ the primary volatile memory 28 as volatile memoryduring the low power mode. The processing chipset 22 remains fullyand/or partially powered to allow access to the primary volatile memory28 during the low power mode.

Referring now to FIG. 4B, an eighth exemplary computer architecture 200that is similar to FIG. 4A is shown. Secondary volatile memory 154 and158 is connected to the secondary processor 104 and the secondarygraphics processor 108, respectively, and is used instead of and/or inaddition to the primary volatile memory 28 during the low power mode.The processing chipset 22 and the primary volatile memory 28 can be shutdown during the low power mode.

Referring now to FIG. 4C, a ninth exemplary computer architecture 210that is similar to FIG. 4A is shown. Embedded volatile memory 174 and176 is provided for the secondary processor 104 and/or the secondarygraphics processor 108, respectively in addition to and/or instead ofthe primary volatile memory 28. In this embodiment, the processingchipset 22 and the primary volatile memory 28 can be shut down duringthe low power mode.

Referring now to FIG. 5, a caching hierarchy 250 for the computerarchitectures illustrated in FIGS. 2A-4C is shown. The HP nonvolatilememory HPDD 50 is located at a lowest level 254 of the caching hierarchy250. Level 254 may or may not be used during the low power mode if theHPDD 50 is disabled and will be used if the HPDD 50 is enabled duringthe low power mode. The LP nonvolatile memory such as LPDD 110 and/orFlash memory 112 is located at a next level 258 of the caching hierarchy250. External volatile memory such as primary volatile memory, secondaryvolatile memory and/or secondary embedded memory is a next level 262 ofthe caching hierarchy 250, depending upon the configuration. Level 2 orsecondary cache comprises a next level 266 of the caching hierarchy 250.Level 1 cache is a next level 268 of the caching hierarchy 250. The CPU(primary and/or secondary) is a last level 270 of the caching hierarchy.The primary and secondary graphics processor use a similar hierarchy.

The computer architecture according to the present invention provides alow power mode that supports less complex processing and graphics. As aresult, the power dissipation of the computer can be reducedsignificantly. For laptop applications, battery life is extended.

Referring now to FIG. 6, a drive control module 300 or host controlmodule for a multi-disk drive system includes a least used block (LUB)module 304, an adaptive storage module 306, and/or a LPDD maintenancemodule 308. The drive control module 300 controls storage and datatransfer between a high-powered disk drive (HPDD) 310 such as a harddisk drive and a low-power disk drive (LPDD) 312 such as a microdrivebased in part on LUB information. The drive control module 300 reducespower consumption by managing data storage and transfer between the HPDDand LPDD during the high and low power modes.

The least used block module 304 keeps track of the least used block ofdata in the LPDD 312. During the low-power mode, the least used blockmodule 304 identifies the least used block of data (such as files and/orprograms) in the LPDD 312 so that it can be replaced when needed.Certain data blocks or files may be exempted from the least used blockmonitoring such as files that relate to the restricted-feature operatingsystem only, blocks that are manually set to be stored in the LPDD 312,and/or other files and programs that are operated during the low powermode only. Still other criteria may be used to select data blocks to beoverwritten, as will be described below.

During the low power mode during a data storing request the adaptivestorage module 306 determines whether write data is more likely to beused before the least used blocks. The adaptive storage module 306 alsodetermines whether read data is likely to be used only once during thelow power mode during a data retrieval request. The LPDD maintenancemodule 308 transfers aged data from the LPDD to the HPDD during the highpower mode and/or in other situations as will be described below.

Referring now to FIG. 7A, steps performed by the drive control module300 are shown. Control begins in step 320. In step 324, the drivecontrol module 300 determines whether there is a data storing request.If step 324 is true, the drive control module 300 determines whetherthere is sufficient space available on the LPDD 312 in step 328. If not,the drive control module 300 powers the HPDD 310 in step 330. In step334, the drive control module 300 transfers the least used data block tothe HPDD 310. In step 336, the drive control module 300 determineswhether there is sufficient space available on the LPDD 312. If not,control loops to step 334. Otherwise, the drive control module 300continues with step 340 and turns off the HPDD 310. In step 344, data tobe stored (e.g. from the host) is transferred to the LPDD 312.

If step 324 is false, the drive control module 300 continues with step350 and determines whether there is a data retrieving request. If not,control returns to step 324. Otherwise, control continues with step 354and determines whether the data is located in the LPDD 312. If step 354is true, the drive control module 300 retrieves the data from the LPDD312 in step 356 and continues with step 324. Otherwise, the drivecontrol module 300 powers the HPDD 310 in step 360. In step 364, thedrive control module 300 determines whether there is sufficient spaceavailable on the LPDD 312 for the requested data. If not, the drivecontrol module 300 transfers the least used data block to the HPDD 310in step 366 and continues with step 364. When step 364 is true, thedrive control module 300 transfers data to the LPDD 312 and retrievesdata from the LPDD 312 in step 368. In step 370, control turns off theHPDD 310 when the transfer of the data to the LPDD 312 is complete.

Referring now to FIG. 7B, a modified approach that is similar to thatshown in FIG. 7A is used and includes one or more adaptive stepsperformed by the adaptive storage module 306. When there is sufficientspace available on the LPDD in step 328, control determines whether thedata to be stored is likely to be used before the data in the least usedblock or blocks that are identified by the least used block module instep 372. If step 372 is false, the drive control module 300 stores thedata on the HPDD in step 374 and control continues with step 324. Bydoing so, the power that is consumed to transfer the least used block(s)to the LPDD is saved. If step 372 is true, control continues with step330 as described above with respect to FIG. 7A.

When step 354 is false during a data retrieval request, controlcontinues with step 376 and determines whether data is likely to be usedonce. If step 376 is true, the drive control module 300 retrieves thedata from the HPDD in step 378 and continues with step 324. By doing so,the power that would be consumed to transfer the data to the LPDD issaved. If step 376 is false, control continues with step 360. As can beappreciated, if the data is likely to be used once, there is no need tomove the data to the LPDD. The power dissipation of the HPDD, however,cannot be avoided.

Referring now to FIG. 7C, a more simplified form of control can also beperformed during low power operation. Maintenance steps can also beperformed during high power and/or low power modes (using the LPDDmaintenance module 308). In step 328, when there is sufficient spaceavailable on the LPDD, the data is transferred to the LPDD in step 344and control returns to step 324. Otherwise, when step 328 is false, thedata is stored on the HPDD in step 380 and control returns to step 324.As can be appreciated, the approach illustrated in FIG. 7C uses the LPDDwhen capacity is available and uses the HPDD when LPDD capacity is notavailable. Skilled artisans will appreciate that hybrid methods may beemployed using various combinations of the steps of FIGS. 7A-7D.

In FIG. 7D, maintenance steps are performed by the drive control module300 upon returning to the high power mode and/or at other times todelete unused or low use files that are stored on the LPDD. Thismaintenance step can also be performed in the low power mode,periodically during use, upon the occurrence of an event such as a diskfull event, and/or in other situations. Control begins in step 390. Instep 392, control determines whether the high power mode is in use. Ifnot, control loops back to step 7D. If step 392 is true, controldetermines whether the last mode was the low power mode in step 394. Ifnot, control returns to step 392. If step 394 is false, control performsmaintenance such as moving aged or low use files from the LPDD to theHPDD in step 396. Adaptive decisions may also be made as to which filesare likely to be used in the future, for example using criteriadescribed above and below in conjunction with FIGS. 8A-10.

Referring now to FIGS. 8A and 8B, storage control systems 400-1, 400-2and 400-3 are shown. In FIG. 8A, the storage control system 400-1includes a cache control module 410 with an adaptive storage controlmodule 414. The adaptive storage control module 414 monitors usage offiles and/or programs to determine whether they are likely to be used inthe low power mode or the high power mode. The cache control module 410communicates with one or more data buses 416, which in turn, communicatewith volatile memory 422 such as L1 cache, L2 cache, volatile RAM suchas DRAM and/or other volatile electronic data storage. The buses 416also communicate with low power nonvolatile memory 424 (such as Flashmemory and/or a LPDD) and/or high power nonvolatile memory 426 such as aHPDD 426. In FIG. 8B, a full-featured and/or restricted featureoperating system 430 is shown to include the adaptive storage controlmodule 414. Suitable interfaces and/or controllers (not shown) arelocated between the data bus and the HPDD and/or LPDD.

In FIG. 8C, a host control module 440 includes the adaptive storagecontrol module 414. The host control module 440 communicates with a LPDD426′ and a hard disk drive 426′. The host control module 440 can be adrive control module, an Integrated Device Electronics (IDE), ATA,serial ATA (SATA) or other controller.

Referring now to FIG. 9, steps performed by the storage control systemsin FIGS. 8A-8C are shown. In FIG. 9, control begins with step 460. Instep 462, control determines whether there is a request for data storageto nonvolatile memory. If not, control loops back to step 462.Otherwise, the adaptive storage control module 414 determines whetherdata is likely to be used in the low-power mode in step 464. If step 464is false, data is stored in the HPDD in step 468. If step 464 is true,the data is stored in the nonvolatile memory 444 in step 474.

Referring now to FIG. 10, one way of determining whether a data block islikely to be used in the low-power mode is shown. A table 490 includes adata block descriptor field 492, a low-power counter field 493, ahigh-power counter field 494, a size field 495, a last use field 496and/or a manual override field 497. When a particular program or file isused during the low-power or high-power modes, the counter field 493and/or 494 is incremented. When data storage of the program or file isrequired to nonvolatile memory, the table 492 is accessed. A thresholdpercentage and/or count value may be used for evaluation. For example,if a file or program is used greater than 80 percent of the time in thelow-power mode, the file may be stored in the low-power nonvolatilememory such as flash memory and/or the microdrive. If the threshold isnot met, the file or program is stored in the high-power nonvolatilememory.

As can be appreciated, the counters can be reset periodically, after apredetermined number of samples (in other words to provide a rollingwindow), and/or using any other criteria. Furthermore, the likelihoodmay be weighted, otherwise modified, and/or replaced by the size field495. In other words, as the file size grows, the required threshold maybe increased because of the limited capacity of the LPDD.

Further modification of the likelihood of use decision may be made onthe basis of the time since the file was last used as recorded by thelast use field 496. A threshold date may be used and/or the time sincelast use may be used as one factor in the likelihood determination.While a table is shown in FIG. 10, one or more of the fields that areused may be stored in other locations and/or in other data structures.An algorithm and/or weighted sampling of two or more fields may be used.

Using the manual override field 497 allows a user and/or the operatingsystem to manually override of the likelihood of use determination. Forexample, the manual override field may allow an L status for defaultstorage in the LPDD, an H status for default storage in the HPDD and/oran A status for automatic storage decisions (as described above). Othermanual override classifications may be defined. In addition to the abovecriteria, the current power level of the computer operating in the LPDDmay be used to adjust the decision. Skilled artisans will appreciatethat there are other methods for determining the likelihood that a fileor program will be used in the high-power or low-power modes that fallwithin the teachings of the present invention.

Referring now to FIGS. 11A and 11B, drive power reduction systems 500-1,500-2 and 500-3 (collectively 500) are shown. The drive power reductionsystem 500 bursts segments of a larger sequential access file such asbut not limited audio and/or video files to the low power nonvolatilememory on a periodic or other basis. In FIG. 11A, the drive powerreduction system 500-1 includes a cache control module 520 with a drivepower reduction control module 522. The cache control module 520communicates with one or more data buses 526, which in turn, communicatewith volatile memory 530 such as L1 cache, L2 cache, volatile RAM suchas DRAM and/or other volatile electronic data storage, nonvolatilememory 534 such as Flash memory and/or a LPDD, and a HPDD 538. In FIG.11B, the drive power reduction system 500-2 includes a full-featuredand/or restricted feature operating system 542 with a drive powerreduction control module 522. Suitable interfaces and/or controllers(not shown) are located between the data bus and the HPDD and/or LPDD.

In FIG. 11C, the drive power reduction system 500-3 includes a hostcontrol module 560 with an adaptive storage control module 522. The hostcontrol module 560 communicates with one or more data buses 564, whichcommunicate with the LPDD 534′ and the hard disk drive 538′. The hostcontrol module 560 can be a drive control module, an Integrated DeviceElectronics (IDE), ATA, serial ATA (SATA) and/or other controller orinterface.

Referring now to FIG. 12, steps performed by the drive power reductionsystems 500 in FIGS. 11A-11C are shown. Control begins the step 582. Instep 584, control determines whether the system is in a low-power mode.If not, control loops back to step 584. If step 586 is true, controlcontinues with step 586 where control determines whether a large datablock access is typically requested from the HPDD in step 586. If not,control loops back to step 584. If step 586 is true, control continueswith step 590 and determines whether the data block is accessedsequentially. If not, control loops back to 584. If step 590 is true,control continues with step 594 and determines the playback length. Instep 598, control determines a burst period and frequency for datatransfer from the high power nonvolatile memory to the low powernonvolatile memory.

In one implementation, the burst period and frequency are optimized toreduce power consumption. The burst period and frequency are preferablybased upon the spin-up time of the HPDD and/or the LPDD, the capacity ofthe nonvolatile memory, the playback rate, the spin-up and steady statepower consumption of the HPDD and/or LPDD, and/or the playback length ofthe sequential data block.

For example, the high power nonvolatile memory is a HPDD that consumes1-2 W during operation, has a spin-up time of 4-10 seconds and acapacity that is typically greater than 20 Gb. The low power nonvolatilememory is a microdrive that consumes 0.3-0.5 W during operation, has aspin-up time of 1-3 seconds, and a capacity of 1-6 Gb. As can beappreciated, the forgoing performance values and/or capacities will varyfor other implementations. The HPDD may have a data transfer rate of 1Gb/s to the microdrive. The playback rate may be 10 Mb/s (for examplefor video files). As can be appreciated, the burst period times thetransfer rate of the HPDD should not exceed the capacity of themicrodrive. The period between bursts should be greater than the spin-uptime plus the burst period. Within these parameters, the powerconsumption of the system can be optimized. In the low power mode, ifthe HPDD is operated to play an entire video such as a movie, asignificant amount of power is consumed. Using the method describedabove, the power dissipation can be reduced significantly by selectivelytransferring the data from the HPDD to the LPDD in multiple burstsegments spaced at fixed intervals at a very high rate (e.g., 100× theplayback rate) and then the HPDD can be shut down. Power savings thatare greater than 50% can easily be achieved.

Referring now to FIG. 13, a multi-disk drive system 640 according to thepresent invention is shown to include a drive control module 650 and oneor more HPDD 644 and one or more LPDD 648. The drive control module 650communicates with a processing device via host control module 651. Tothe host, the multi-disk drive system 640 effectively operates the HPDD644 and LPDD 648 as a unitary disk drive to reduce complexity, improveperformance and decrease power consumption, as will be described below.The host control module 651 can be an IDE, ATA, SATA and/or othercontrol module or interface.

Referring now to FIG. 14, in one implementation the drive control module650 includes a hard disk controller (HDC) 653 that is used to controlone or both of the LPDD and/or HPDD. A buffer 656 stores data that isassociated the control of the HPDD and/or LPDD and/or aggressivelybuffers data to/from the HPDD and/or LPDD to increase data transferrates by optimizing data block sizes. A processor 657 performsprocessing that is related to the operation of the HPDD and/or LPDD.

The HPDD 648 includes one or more platters 652 having a magnetic coatingthat stores magnetic fields. The platters 652 are rotated by a spindlemotor that is schematically shown at 654. Generally the spindle motor654 rotates the platter 652 at a fixed speed during the read/writeoperations. One or more read/write arms 658 move relative to theplatters 652 to read and/or write data to/from the platters 652. Sincethe HPDD 648 has larger platters than the LPDD, more power is requiredby the spindle motor 654 to spin-up the HPDD and to maintain the HPDD atspeed. Usually, the spin-up time is higher for HPDD as well.

A read/write device 659 is located near a distal end of the read/writearm 658. The read/write device 659 includes a write element such as aninductor that generates a magnetic field. The read/write device 659 alsoincludes a read element (such as a magneto-resistive (MR) element) thatsenses the magnetic field on the platter 652. A preamp circuit 660amplifies analog read/write signals.

When reading data, the preamp circuit 660 amplifies low level signalsfrom the read element and outputs the amplified signal to the read/writechannel device. While writing data, a write current is generated whichflows through the write element of the read/write device 659 and isswitched to produce a magnetic field having a positive or negativepolarity. The positive or negative polarity is stored by the platter 652and is used to represent data. The LPDD 644 also includes one or moreplatters 662, a spindle motor 664, one or more read/write arms 668, aread/write device 669, and a preamp circuit 670.

The HDC 653 communicates with the host control module 651 and with afirst spindle/voice coil motor (VCM) driver 672, a first read/writechannel circuit 674, a second spindle/VCM driver 676, and a secondread/write channel circuit 678. The host control module 651 and thedrive control module 650 can be implemented by a system on chip (SOC)684. As can be appreciated, the spindle VCM drivers 672 and 676 and/orread/write channel circuits 674 and 678 can be combined. The spindle/VCMdrivers 672 and 676 control the spindle motors 654 and 664, which rotatethe platters 652 and 662, respectively. The spindle/VCM drivers 672 and676 also generate control signals that position the read/write arms 658and 668, respectively, for example using a voice coil actuator, astepper motor or any other suitable actuator.

Referring now to FIGS. 15-17, other variations of the multi-disk drivesystem are shown. In FIG. 15, the drive control module 650 may include adirect interface 680 for providing an external connection to one or moreLPDD 682. In one implementation, the direct interface is a PeripheralComponent Interconnect (PCI) bus, a PCI Express (PCIX) bus, and/or anyother suitable bus or interface.

In FIG. 16, the host control module 651 communicates with both the LPDD644 and the HPDD 648. A low power drive control module 650LP and a highpower disk drive control module 650HP communicate directly with the hostcontrol module. Zero, one or both of the LP and/or the HP drive controlmodules can be implemented as a SOC.

In FIG. 17, one exemplary LPDD 682 is shown to include an interface 690that supports communications with the direct interface 680. As set forthabove, the interfaces 680 and 690 can be a Peripheral ComponentInterconnect (PCI) bus, a PCI Express (PCIX) bus, and/or any othersuitable bus or interface. The LPDD 682 includes an HDC 692, a buffer694 and/or a processor 696. The LPDD 682 also includes the spindle/VCMdriver 676, the read/write channel circuit 678, the platter 662, thespindle motor 665, the read/write arm 668, the read element 669, and thepreamp 670, as described above. Alternately, the HDC 653, the buffer 656and the processor 658 can be combined and used for both drives. Likewisethe spindle/VCM driver and read channel circuits can optionally becombined. In the embodiments in FIGS. 13-17, aggressive buffering of theLPDD is used to increase performance. For example, the buffers are usedto optimize data block sizes for optimum speed over host data buses.

In conventional computer systems, a paging file is a hidden file on theHPDD or HP nonvolatile memory that is used by the operating system tohold parts of programs and/or data files that do not fit in the volatilememory of the computer. The paging file and physical memory, or RAM,define virtual memory of the computer. The operating system transfersdata from the paging file to memory as needed and returns data from thevolatile memory to the paging file to make room for new data. The pagingfile is also called a swap file.

Referring now to FIGS. 18-20, the present invention utilizes the LPnonvolatile memory such as the LPDD and/or flash memory to increase thevirtual memory of the computer system. In FIG. 18, an operating system700 allows a user to define virtual memory 702. During operation, theoperating system 700 addresses the virtual memory 702 via one or morebuses 704. The virtual memory 702 includes both volatile memory 708 andLP nonvolatile memory 710 such as Flash memory and/or a LPDD.

Referring now to FIG. 19, the operating system allows a user to allocatesome or all of the LP nonvolatile memory 710 as paging memory toincrease virtual memory. In step 720, control begins. In step 724, theoperating system determines whether additional paging memory isrequested. If not, control loops back to step 724. Otherwise, theoperating system allocates part of the LP nonvolatile memory for pagingfile use to increase the virtual memory in step 728.

In FIG. 20, the operating system employs the additional LP nonvolatilememory as paging memory. Control begins in step 740. In step 744,control determines whether the operating system is requesting a datawrite operation. If true, control continues with step 748 and determineswhether the capacity of the volatile memory is exceeded. If not, thevolatile memory is used for the write operation in step 750. If step 748is true, data is stored in the paging file in the LP nonvolatile memoryin step 754. If step 744 is false, control continues with step 760 anddetermines whether a data read is requested. If false, control loopsback to step 744. Otherwise, control determines whether the addresscorresponds to a RAM address in step 764. If step 764 is true, controlreads data from the volatile memory in step 764 and continues with step744. If step 764 is false, control reads data from the paging file inthe LP nonvolatile memory in step 770 and control continues with step744.

As can be appreciated, using LP nonvolatile memory such as Flash memoryand/or the LPDD to increase the size of virtual memory will increase theperformance of the computer as compared to systems employing the HPDD.Furthermore, the power consumption will be lower than systems using theHPDD for the paging file. The HPDD requires additional spin-up time dueto its increased size, which increases data access times as compared tothe Flash memory, which has no spin-up latency, and/or the LPDD, whichhas a shorter spin-up time and lower power dissipation.

Referring now to FIG. 21, a Redundant Array of Independent Disks (RAID)system 800 is shown to include one or more servers and/or clients 804that communicate with a disk array 808. The one or more servers and/orclients 804 include a disk array controller 812 and/or an arraymanagement module 814. The disk array controller 812 and/or the arraymanagement module 814 receive data and perform logical to physicaladdress mapping of the data to the disk array 808. The disk arraytypically includes a plurality of HPDD 816.

The multiple HPDDs 816 provide fault tolerance (redundancy) and/orimproved data access rates. The RAID system 800 provides a method ofaccessing multiple individual HPDDs as if the disk array 808 is onelarge hard disk drive. Collectively, the disk array 808 may providehundreds of Gb to 10's to 100's of Tb of data storage. Data is stored invarious ways on the multiple HPDDs 816 to reduce the risk of losing allof the data if one drive fails and to improve data access time.

The method of storing the data on the HPDDs 816 is typically called aRAID level. There are various RAID levels including RAID level 0 or diskstriping. In RAID level 0 systems, data is written in blocks acrossmultiple drives to allow one drive to write or read a data block whilethe next is seeking the next block. The advantages of disk stripinginclude the higher access rate and full utilization of the arraycapacity. The disadvantage is there is no fault tolerance. If one drivefails, the entire contents of the array become inaccessible.

RAID level 1 or disk mirroring provides redundancy by writing twice—onceto each drive. If one drive fails, the other contains an exact duplicateof the data and the RAID system can switch to using the mirror drivewith no lapse in user accessibility. The disadvantages include a lack ofimprovement in data access speed and higher cost due to the increasednumber of drives (2N) that are required. However, RAID level 1 providesthe best protection of data since the array management software willsimply direct all application requests to the surviving HPDDs when oneof the HPDDs fails.

RAID level 3 stripes data across multiple drives with an additionaldrive dedicated to parity, for error correction/recovery. RAID level 5provides striping as well as parity for error recovery. In RAID level 5,the parity block is distributed among the drives of the array, whichprovides more balanced access load across the drives. The parityinformation is used to recovery data if one drive fails. Thedisadvantage is a relatively slow write cycle (2 reads and 2 writes arerequired for each block written). The array capacity is N−1, with aminimum of 3 drives required.

RAID level 0+1 involves stripping and mirroring without parity. Theadvantages are fast data access (like RAID level 0), and single drivefault tolerance (like RAID level 1). RAID level 0+1 still requires twicethe number of disks (like RAID level 1). As can be appreciated, therecan be other RAID levels and/or methods for storing the data on thearray 808.

Referring now to FIGS. 22A and 22B, a RAID system 834-1 according to thepresent invention includes a disk array 836 that includes X HPDD and adisk array 838 that includes Y LPDD. One or more clients and/or aservers 840 include a disk array controller 842 and/or an arraymanagement module 844. While separate devices 842 and 844 are shown,these devices can be integrated if desired. As can be appreciated, X isgreater than or equal to 2 and Y is greater than or equal to 1. X can begreater than Y, less than Y and/or equal to Y. For example, FIG. 22Bshows a RAID system 834-1′ where X=Y=Z.

Referring now to FIGS. 23A, 23B, 24A and 24B, RAID systems 834-2 and834-3 are shown. In FIG. 23A, the LPDD disk array 838 communicates withthe servers/clients 840 and the HPDD disk array 836 communicates withthe LPDD disk array 838. The RAID system 834-2 may include a managementbypass path that selectively circumvents the LPDD disk array 838. As canbe appreciated, X is greater than or equal to 2 and Y is greater than orequal to 1. X can be greater than Y, less than Y and/or equal to Y. Forexample, FIG. 23B shows a RAID system 834-2′ case where X=Y=Z. In FIG.24A, the HPDD disk array 836 communicates with the servers/clients 840and the LPDD disk array 838 communicates with the HPDD disk array 836.The RAID system 834-2 may include a management bypass path shown bydotted line 846 that selectively circumvents the LPDD disk array 838. Ascan be appreciated, X is greater than or equal to 2 and Y is greaterthan or equal to 1. X can be greater than Y, less than Y and/or equal toY. For example, FIG. 24B shows a RAID system 834-3′ where X=Y=Z. Thestrategy employed may include write through and/or write back in FIGS.23A-24B.

The array management module 844 and/or the disk controller 842 utilizesthe LPDD disk array 838 to reduce power consumption of the HPDD diskarray 836. Typically, the HPDD disk array 808 in the conventional RAIDsystem in FIG. 21 is kept on at all times during operation to supportthe required data access times. As can be appreciated, the HPDD diskarray 808 dissipates a relatively high amount of power. Furthermore,since a large amount of data is stored in the HPDD disk array 808, theplatters of the HPDDs are typically as large as possible, which requireshigher capacity spindle motors and increases the data access times sincethe read/write arms move further on average.

According to the present invention, the techniques that are describedabove in conjunction with FIGS. 6-17 are selectively employed in theRAID system 834 as shown in FIG. 22B to reduce power consumption anddata access times. While not shown in FIGS. 22A and 23A-24B, the otherRAID systems according to the present invention may also use thesetechniques. In other words, the LUB module 304, adaptive storage module306 and/or the LPDD maintenance module that are described in FIGS. 6 and7A-7D are selectively implemented by the disk array controller 842and/or the array management controller 844 to selectively store data onthe LPDD disk array 838 to reduce power consumption and data accesstimes. The adaptive storage control module 414 that is described inFIGS. 8A-8C, 9 and 10 may also be selectively implemented by the diskarray controller 842 and/or the array management controller 844 toreduce power consumption and data access times. The drive powerreduction module 522 that is described FIGS. 11A-11C and 12 may also beimplemented by the disk array controller 842 and/or the array managementcontroller 844 to reduce power consumption and data access times.Furthermore, the multi-drive systems and/or direct interfaces that areshown in FIGS. 13-17 may be implemented with one or more of the HPDD inthe HPDD disk array 836 to increase functionality and to reduce powerconsumption and access times.

Referring now to FIG. 25, a network attached storage (NAS) system 850according to the prior art is shown to include storage devices 854,storage requesters 858, a file server 862, and a communications system866. The storage devices 854 typically include disc drives, RAIDsystems, tape drives, tape libraries, optical drives, jukeboxes, and anyother storage devices to be shared. The storage devices 854 arepreferably but not necessarily object oriented devices. The storagedevices 854 may include an I/O interface for data storage and retrievalby the requesters 858. The requesters 858 typically include serversand/or clients that share and/or directly access the storage devices854.

The file server 862 performs management and security functions such asrequest authentication and resource location. The storage devices 854depend on the file server 862 for management direction, while therequesters 858 are relieved of storage management to the extent the fileserver 862 assumes that responsibility. In smaller systems, a dedicatedfile server may not be desirable. In this situation, a requester maytake on the responsibility for overseeing the operation of the NASsystem 850. As such, both the file server 862 and the requester 858 areshown to include management modules 870 and 872, respectively, thoughone or the other and/or both may be provided. The communications system866 is the physical infrastructure through which components of the NASsystem 850 communicate. It preferably has properties of both networksand channels, has the ability to connect all components in the networksand the low latency that is typically found in a channel.

When the NAS system 850 is powered up, the storage devices 854 identifythemselves either to each other or to a common point of reference, suchas the file server 862, one or more of the requesters 858 and/or to thecommunications system 866. The communications system 866 typicallyoffers network management techniques to be used for this, which areaccessible by connecting to a medium associated with the communicationssystem. The storage devices 854 and requesters 858 log onto the medium.Any component wanting to determine the operating configuration can usemedium services to identify all other components. From the file server862, the requesters 858 learn of the existence of the storage devices854 they could have access to, while the storage devices 854 learn whereto go when they need to locate another device or invoke a managementservice like backup. Similarly the file server 862 can learn of theexistence of storage devices 854 from the medium services. Depending onthe security of a particular installation, a requester may be deniedaccess to some equipment. From the set of accessible storage devices, itcan then identify the files, databases, and free space available.

At the same time, each NAS component can identify to the file server 862any special considerations it would like known. Any device level serviceattributes could be communicated once to the file server 862, where allother components could learn of them. For instance, a requester may wishto be informed of the introduction of additional storage subsequent tostartup, this being triggered by an attribute set when the requesterlogs onto the file server 862. The file server 862 could do thisautomatically whenever new storage devices are added to theconfiguration, including conveying important characteristics, such as itbeing RAID 5, mirrored, and so on.

When a requester must open a file, it may be able to go directly to thestorage devices 854 or it may have to go to the file server forpermission and location information. To what extent the file server 854controls access to storage is a function of the security requirements ofthe installation.

Referring now to FIG. 26, a network attached storage (NAS) system 900according to the present invention is shown to include storage devices904, requesters 908, a file server 912, and a communications system 916.The storage devices 904 include the RAID system 834 and/or multi-diskdrive systems 930 described above in FIGS. 6-19. The storage devices 904may also include disc drives, RAID systems, tape drives, tape libraries,optical drives, jukeboxes, and/or any other storage devices to be sharedas described above. As can be appreciated, using the improved RAIDsystems and/or multi-disk drive systems 930 will reduce the powerconsumption and data access times of the NAS system 900.

Those skilled in the art can now appreciate from the foregoingdescription that the broad teachings of the present invention can beimplemented in a variety of forms. Therefore, while this invention hasbeen described in connection with particular examples thereof, the truescope of the invention should not be so limited since othermodifications will become apparent to the skilled practitioner upon astudy of the drawings, the specification and the following claims.

1. A processing system, comprising: a processor; low power (LP)nonvolatile memory that communicates with said processor; high power(HP) nonvolatile memory that communicates with said processor; and adrive control module, wherein said processing system manages data usinga cache hierarchy comprising (i) a HP nonvolatile memory level for datain said HP nonvolatile memory and (ii) a LP nonvolatile memory level fordata in said LP nonvolatile memory, wherein said LP nonvolatile memorylevel has a higher level in said cache hierarchy than said HPnonvolatile memory level, and wherein said drive control module at leastone of: controls data access to said LP nonvolatile memory and said HPnonvolatile memory independent of control signals from a host computer;or controls data transfer between said LP nonvolatile memory and said HPnonvolatile memory independent of control signals from the hostcomputer.
 2. The processing system of claim 1, further comprising: levelone cache that is associated with said processor; volatile memory thatcommunicates with said processor; and level two cache that communicateswith said processor.
 3. The processing system of claim 2, wherein saidcache hierarchy further comprises: a volatile memory level; a secondlevel for data in said level two cache; a first level for data in saidlevel one cache; and a CPU level for data in said processor.
 4. Theprocessing system of claim 1, wherein said HP nonvolatile memoryincludes a HP disk drive with a platter having a diameter greater than1.8″.
 5. The processing system of claim 1, wherein said LP nonvolatilememory includes at least one of flash memory or a LP disk drive having aplatter with a diameter less than or equal to 1.8″.
 6. A processingdevice having high power (HP) and low power (LP) modes, said processingdevice comprising: a primary processing means for processing data; asecondary processing means for processing data; a primary graphicsprocessing means for processing data; a secondary graphics processingmeans for processing data; a processing chipset; an input and output(I/O) chipset; first nonvolatile storing means for communicating withsaid processing device and for storing a first operating system that isexecuted by said processing device during said HP mode; and secondnonvolatile storing means for communicating with said processing deviceand for storing a second operating system that is executed by saidprocessing device during said LP mode, wherein said primary processingmeans and said primary graphics processing means communicate with saidfirst nonvolatile storing means via said processing chipset, said I/Ochipset, and a system bus, and wherein said secondary processing meansand said secondary graphics processing means communicate with saidsecond nonvolatile storing means via said processing chipset, said I/Ochipset, and a peripheral component interconnect bus.
 7. The processingdevice of claim 6, wherein: said primary processing means communicateswith said first nonvolatile storing means and executes said firstoperating system during said HP mode; and said secondary processingmeans communicates with said second nonvolatile storing means andexecutes said second operating system during said LP mode.
 8. Theprocessing device of claim 6, wherein said first operating system is afull-featured operating system, and said second operating system is arestricted-feature operating system.
 9. The processing device of claim7, wherein: said primary graphics processing means communicates withsaid primary processing means and supports full-featured graphicsprocessing during said HP mode; and said secondary graphics processingdevice communicates with said secondary processing means and supportsrestricted-feature graphics processing during said LP mode.
 10. Theprocessing device of claim 8, wherein said full-featured operatingsystem and said restricted-feature operating system share a common dataformat.
 11. A processing device, comprising: processing means forprocessing data; low power (LP) nonvolatile storing means for storingdata and that for communicating with said processing means; high power(HP) nonvolatile storing means for storing data and for communicatingwith said processing means; and drive control means for controllingaccess to said LP nonvolatile storing means and said HP nonvolatilestoring means, wherein said processing device manages data using a cachehierarchy comprising (i) a HP nonvolatile level for data in said HPnonvolatile storing means and (ii) a LP nonvolatile level for data insaid LP nonvolatile storing means, wherein said LP nonvolatile level hasa higher level in said cache hierarchy than said HP nonvolatile level,and wherein said drive control means at least one of: controls dataaccess to said LP nonvolatile storing means and said HP nonvolatilestoring means independent of control signals from a host computer; orcontrols data transfer between said LP nonvolatile storing means andsaid HP nonvolatile storing means independent of control signals fromthe host computer.
 12. The processing device of claim 11, furthercomprising: first cache means for storing data that is associated withsaid processing means; volatile storing means for storing data and forcommunicating with said processing means; and second cache means forstoring data and communicating with said processing means.
 13. Theprocessing device of claim 12, wherein said cache hierarchy furthercomprises: a volatile level, a second level for data in said secondcache means; a first level for data in said first cache means; and a CPUlevel for data in said processing means.
 14. The processing device ofclaim 11, wherein said HP nonvolatile storing means includes a HP diskdrive with a platter having a diameter greater than 1.8″.
 15. Theprocessing device of claim 11, wherein said LP nonvolatile storing meansincludes at least one of flash storing means or a LP disk drive having aplatter with a diameter less than or equal to 1.8″.
 16. A method foroperating a processing device having high power (HP) and low power (LP)modes, the method comprising: providing a primary processor; providing asecondary processor; providing a primary graphics processor; providing asecondary graphics processor; providing a processing chipset; providingan input and output (I/O) chipset; storing a first operating system thatis executed by said processing device during said HP mode in a firstnonvolatile memory; storing a second operating system that is executedby said processing device during said LP mode in a second nonvolatilememory; executing said first operating system including using saidprimary processor and said primary graphics processor to communicatewith said first nonvolatile memory via said processing chipset, said I/Ochipset, and a system bus; and executing said second operating systemincluding using said secondary processor and said secondary graphicsprocessor to communicate with said second nonvolatile memory via saidprocessing chipset, said I/O chipset, and a peripheral componentinterconnect bus.
 17. The method of claim 16, further comprising:executing said first operating system during said HP mode using saidprimary processor to communicate with said first nonvolatile memory; andexecuting said second operating system during said LP mode using saidsecondary processor to communicate with said second nonvolatile memory.18. The method of claim 16, wherein said first operating system is afull-featured operating system, and said second operating system is arestricted-feature operating system.
 19. The method of claim 16, furthercomprising: supporting full-featured graphics processing during said HPmode; and supporting restricted-feature graphics processing during saidLP mode.
 20. The method of claim 18, further comprising using a commondata format for said full-featured operating system and saidrestricted-feature operating system.
 21. A method for operating aprocessing device, the method comprising: providing a processor thatcommunicates with low power (LP) nonvolatile memory and high power (HP)nonvolatile memory; managing data using a cache hierarchy comprising aHP nonvolatile memory level for data in said HP nonvolatile memory and aLP nonvolatile memory level for data in said LP nonvolatile memory;assigning a higher level in said cache hierarchy to said LP nonvolatilememory level than said HP nonvolatile memory level; and at least one ofcontrolling data access to said LP nonvolatile memory and said HPnonvolatile memory independent of control signals from a host computer,or controlling data transfer between said LP nonvolatile memory and saidHP nonvolatile memory independent of control signals from the hostcomputer.
 22. The method of claim 21, wherein said HP nonvolatile memoryincludes a HP disk drive with a platter having a diameter greater than1.8″.
 23. The method of claim 21, wherein said LP nonvolatile memoryincludes at least one of flash memory or a LP disk drive having aplatter with a diameter less than or equal to 1.8″.
 24. A devicecomprising: a processing unit having high power (HP) and low power (LP)modes, said processing unit comprising a primary processing devicecomprising first transistors, and a secondary processing devicecomprising second transistors; a first operating system that is executedby said processing unit during said HP mode; and a second operatingsystem that is executed by said processing unit during said LP mode,wherein said first transistors operate at a first duty cycle, andwherein said second transistors operate at a second duty cycle that isdifferent than said first duty cycle.
 25. The device of claim 24,wherein said primary processing device that executes said firstoperating system during said HP mode; and said secondary processingdevice that executes said second operating system during said LP mode.26. The device of claim 24, wherein said first operating system is afull-featured operating system.
 27. The device of claim 26, wherein saidsecond operating system is a restricted-feature operating system. 28.The device of claim 24, wherein said processing unit further comprises:a primary graphics processing device that supports full-featuredgraphics processing during said HP mode; and a secondary graphicsprocessing device that supports restricted-feature graphics processingduring said LP mode.
 29. The device of claim 27, wherein saidfull-featured operating system and said restricted-feature operatingsystem share a common data format.
 30. A method for operating a device,the method comprising: operating a processing unit in high power (HP)and low power (LP) modes; implementing said processing unit using aprimary processing device and secondary processing device; executing afirst operating system during said HP mode while operating transistorsof said primary processing device at a first duty cycle; and executing asecond operating system during said LP mode while operating transistorsof said secondary processing device at a second duty cycle that isdifferent than said first duty cycle.
 31. The method of claim 30,further comprising: executing said first operating system using saidprimary processing device during said HP mode; and executing said secondoperating system using said secondary processing device during said LPmode.
 32. The method of claim 30, wherein said first operating system isa full-featured operating system.
 33. The method of claim 32, whereinsaid second operating system is a restricted-feature operating system.34. The method of claim 30, further comprising: supporting full-featuredgraphics processing during said HP mode; and supportingrestricted-feature graphics processing during said LP mode.
 35. Themethod of claim 33, further comprising sharing a common data formatbetween said full-featured operating system and said restricted-featureoperating system.
 36. A device comprising: processing means forprocessing data and having HP and LP modes; first operating means forcontrolling system resources and processes during said HP mode; andsecond operating means for controlling system resources and processesduring said LP mode, wherein said processing means comprises: primaryprocessing means for processing data; and secondary processing means forprocessing data, wherein transistors of said primary processing meansoperate at a first duty cycle; and wherein transistors of said secondaryprocessing means operate at a second duty cycle that is different thansaid first duty cycle.
 37. The device of claim 36, wherein: said primaryprocessing means executes said first operating means during said HPmode; and said secondary processing means executes said second operatingmeans during said LP mode.
 38. The device of claim 36, wherein saidfirst operating means includes a full-featured operating system.
 39. Thedevice of claim 38, wherein said second operating means includes arestricted-feature operating system.
 40. The device of claim 36, whereinsaid processing means further comprises: primary graphics processingmeans for supporting full-featured graphics processing during said HPmode; and secondary graphics processing means for supportrestricted-feature graphics processing during said LP mode.
 41. Thedevice of claim 39, wherein said full-featured operating system and saidrestricted-feature operating system share a common data format.
 42. Theprocessing device of claim 6, wherein said secondary processing meansand said secondary graphics processing means communicate with saidsecond nonvolatile storing means via said system bus.
 43. The processingdevice of claim 6, wherein at least one of the secondary processingmeans and said secondary graphics processing means is directly connectedto said processing chipset.
 44. The processing device of claim 6,wherein: the first nonvolatile storing means comprises a HP disk drive;and the second nonvolatile storing means comprises a LP disk drive.